fix(README): wrap contact email in autolink brackets

Unblocks markdownlint MD034/no-bare-urls failure on CI.

Same fix as the one already on main (via PR #21). Cherry-picked here
so this branch's CI passes; a future rebase onto main will absorb it.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: sjennings

README.md

@@ -113,7 +113,7 @@ BMGD: Great choice! Here's what I recommend...
 
 ## Support BMad
 
-BMad is free for everyone and always will be. Star this repo, [buy me a coffee](https://buymeacoffee.com/bmad), or email contact@bmadcode.com for corporate sponsorship.
+BMad is free for everyone and always will be. Star this repo, [buy me a coffee](https://buymeacoffee.com/bmad), or email <contact@bmadcode.com> for corporate sponsorship.
 
 ## License